A route string is a string with 2 special constructions:
- :string: :string denotes a named parameter (available later as $request->getParameter('string'))
- *: * match an indefinite number of parameters in a route

* suffix: The default suffix
* variable_prefixes: An array of characters that starts a variable name (: by default)
* segment_separators: An array of allowed characters for segment separators (/ and . by default)
* variable_regex: A regex that match a valid variable name ([\w\d_]+ by default)
* generate_shortest_url: Whether to generate the shortest URL possible (true by default)
* extra_parameters_as_query_string: Whether to generate extra parameters as a query string
* lookup_cache_dedicated_keys: Whether to use dedicated keys for parse/generate cache (false by default)
WARNING: When this option is activated, do not use sfFileCache; use a fast access
cache backend (like sfAPCCache).